Means for controlling the draft in locomotive smoke-boxes



W. J. McCARROLL.

MEANS FOR CONTROLLING THE DRAFT IN LOCOMOTIVE SMOKE BOXES.

2 SHEETSSHEET I.

Patented Mar. 16, 1920.

APPLICATION FILED MAY29,1918.

Y W J. MCCARROLL. MEANS FOR CONTROLLING THE DRAFT IN LOCOMOTIVE SMOK EBOXES.

AEPLICATION FILED M129, 1918.

1,333,861. Patented Mar. 16, 1920.

2 SHEEYS-SHEET 2.

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WILLIAM J. MQCARROLL, F PHILADELPHIA, PENNSYLVANIA.

MEANS FOR CONTROLLING THE DRAFT IN LOGOMOTIVE SMOKE-BOXES.

Specification of Letters Patent.

Patented Mar. 16, 1920.

Application filed May 29, 1918. Serial No. 237,302.

7 '0 all whom it may concern Be it known that I, WILLIAM J. MCCAR- ROLL, a citizen of the United States, residing in Philadelphia, Pennsylvania, have invented certain Improvements in Means for Controlling the Draft in Locomotive Smoke- Boxes, of which the following is a specification.

One object of my invention is to provide means for breaking or reducing the vacuum in the smoke box of a locomotive at certain times so as to control the draft and prevent destroying the bed of the fire and avoid injuring the tubes and fire box sheets of the locomotive. lVhen a locomotive is slipping, for instance, an extremely heavy draft occurs which damages the bed of fire in the fire box; this reduces the steam pressure and requires a considerable amount of extra fuel and hard work to reestablish the fire and bring the steam to the pressure desired.

A still further object of the invention is to provide means whereby the flow of the steam to operate the device is controlled from the cab of the locomotive.

In the accompanying drawings Figure 1, is a longitudinal sectional view through the smoke box of a locomotive, illustrating my invention;

Fig. 2, is a transverse sectional view of the same;

Fig. 3, is an enlarged sectional view showing the valve structure which I prefer to use for controlling the flow of steam to the nozzle in the smoke box by means in the cab of a locomotive; and

Fig. 4, is a diagrammatic sectional view, illustrating my invention applied to a locomotive.

Referring to the drawings, 1 is the boiler of a locomotive and 2 is the smoke box. is the fire box having the usual grate 4t. 3 is the stack. 6 is the forward tube sheet and 7 is the rear tube sheet. 8, 8 are the tubes. 9 is the exhaust nozzle leading from the cylinders of-the locomotive. 10 is the cab. 11 is a nozzle, which is located in the smoke box 2, and is arranged in the present instance diagonally so to direct a spray or" steam across the space between the forward tube-sheet O and the nozzle 9 and the stack 5, although this nozzle 11 may be lo cated in other parts without'dcparting from the main features of the invention. In some instances, this nozzle may be duplicated, particularly on large locomotives where an increased amount of steam is necessary to break the partial vacuum caused by the blast of extra steam issuing from the nozzle 9 and into the stack 5. In the present instance, the steam nozzle 11 is attached to a steam pipe 12, which is coupled to a valve casing 13 connected to a steam supply pipe 14. A valve 15 in the valve casing 13 controls the flow of steam from the supply pipe 1 1 to the pipe 12 and nozzle 11. In the present instance, this valve is attached by a rod 17 to a piston 16, which is adapted to an air cylinder 18 communicating with an air pipe 19 leading to the cab of the locomotive at which point a suitable air valve 20 is provided for controlling the flow of air from any suitable source of supply to the cylinder 18. By this means, the steam issuing from the nozzle 11 is under the control of the engineer in the cab of the locomotive. In some instances, the valve 15 may be controlled by means, other than the air connections shown, but the device should be under the control of the engineer in the cab.

When a locomotive is starting a train the heavy exhaust pulls on the fire and consumes considerable fuel and frequently tears holes in the fire bed and damages it to a considerable extent. In order to avoid this, the fireman often opens the fire door, or partially opens it, to avoid the damaging efiect of the heavy exhaust on the fire. During this period, cold air enters through the open doorway, which has the effect to change the .temperaturein the fire box and this temperature must be quickly restored. This method of preventing the damage to the fire bed often has a serious effect on the fire box sheets and tubes by starting leaks in the fiues and at the seams and to restore the fire bed when damaged requires not only a considerable amount of extra fuel, but also necessitates hard work and frequently a loss of steam pressure and time in bringing the steam to the maximum pressure.

By the use of my device, when a locomotive is in service, or at a station, the maxiin service, steam escaping from the nozzle connected to the cylinders creates a partlal vacuum in the smoke box which causes a draft through the tubes and fire, and draws the air from the ash pit through the bed of fuel which supports combustion.

By the use of my imprdvement the steam, when liberated, through the nozzle 11, expands in the smoke box to such a volume that a vacuum cannot be created, thereby checking the effect on the fire. The temperature in the fire box can be maintained more evenly than heretofore by the use of my improved device. Furthermore, when a locomotive is starting, the heavy exhaust carries with it quantites of cinders, dust and black smoke, which will be obviated to a considerable extent by the use of the device hereinbefore described.

I claim: I

1. The combination in a locomotive having a boiler provided with front and rear tube sheets and connecting tubes, a smoke box, a stack communicating therewith and an exhaust nozzle under the stack, of a steam pipe having a nozzle extending into the smoke box and discharging upwardly and delivering substantially a curtain of steam transversely across the space between the front tube sheet and the stack and exhaust nozzle for the purpose of preventing the creation of a vacuum when an excessive draft is produced, and means for controlling the flow of steam from said nozzle.

2. The combination in a locomotive having a smoke box, and a boiler with front tube sheet, of a stack and an exhaust nozzle, means for delivering steam across the space between the front tube sheet and said stack and exhaust nozzle, which space represents the zone receiving the most highly heated products of combustion, said steam expanding in said space and forming substantially a retarding curtain in the path of said products and adapted to prevent the creation of a vacuum in the smoke box when an excessive draft is produced, and means, at the cab of the locomotive, for controlling the flow of steam from said nozzle.

In witness whereof I affix my signature.

WILLIAM J. MoCAR-R-OL'L. 

